This invention relates to an Oldham coupling which is manufactured in a simplified manner.
Scroll compressors are becoming widely utilized in refrigerant compression applications. In a typical scroll compressor a first scroll member has a base and a generally spiral wrap extending from the base. The wrap of the first scroll member interfits with a spiral wrap of a second scroll member, and the scroll member is driven to orbit relative to the first scroll member to compress an entrapped refrigerant. The orbiting movement is achieved from a rotary motor which is connected to the second scroll member through a non-rotation coupling. Typically, an Oldham coupling is provided. The Oldham coupling includes keys which slide in slot structures on the second scroll member, and which in turn has keys extending into slots in a crankcase which supports the second scroll member. In some Oldham couplings, the first scroll member receives the keys rather than the crankcase. The Oldham coupling can move in the slots in the crankcase along a linear path. This allows rotation of the drive motor to be translated into orbiting movement of the second scroll member.
The Oldham coupling is a relatively simple part, but it must meet several design criteria. In particular, the Oldham coupling must have an interior bore which will allow it to slide as described above while remaining out of contact with several components of the compressor which are positioned radially inwardly of the bore""s inner periphery. Moreover, the Oldham coupling ring must have sufficient wall thickness throughout its entire periphery such that the part will be sufficiently robust for reliable use. Finally, the inner periphery of the Oldham coupling ring cannot be so complex that it is difficult or unduly expensive to manufacture.
In the disclosed embodiment of this invention, an Oldham coupling ring has a generally cylindrical inner periphery. Two opposed circular arcs are centered on a common axis, and are associated with the portions of the Oldham coupling which are received in keyways in the crankcase. The circular portions have a pair of angled portions at each of their circumferential extremes. The angled portions merge into flat portions which are positioned radially inwardly of the slots on the ring which receive keys from the orbiting scroll member. The inventive Oldham coupling ring is a relatively simple part to manufacture, in that its inner periphery is formed to be generally circular, with the angled portions on the flat portions being relatively simple portions to manufacture.
In another embodiment, there are three of the angled portions at each of the circumferential extends. This adds additional size to the ring at the area where the angled portions are merging into the flat portions.
These and other features of the present invention can be best understood from the following specification and drawings, the following of which is a brief description.